74391821 has 32 divisors (see below), whose sum is σ = 94832640. Its totient is φ = 56890944.

The previous prime is 74391817. The next prime is 74391839. The reversal of 74391821 is 12819347.

It is a cyclic number.

It is not a de Polignac number, because 74391821 - 2² = 74391817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (74391221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 253751 + ... + 254043.

It is an arithmetic number, because the mean of its divisors is an integer number (2963520).

Almost surely, 2^74391821 is an apocalyptic number.

It is an amenable number.

74391821 is a deficient number, since it is larger than the sum of its proper divisors (20440819).

74391821 is a wasteful number, since it uses less digits than its factorization.

74391821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425.

The product of its digits is 12096, while the sum is 35.

The square root of 74391821 is about 8625.0693330547. The cubic root of 74391821 is about 420.5733307620.

The spelling of 74391821 in words is "seventy-four million, three hundred ninety-one thousand, eight hundred twenty-one".